#!/bin/bash

# -------------------------------------------------------------------------- #
# Copyright 2002-2023, OpenNebula Project, OpenNebula Systems                #
#                                                                            #
# Licensed under the Apache License, Version 2.0 (the "License"); you may    #
# not use this file except in compliance with the License. You may obtain    #
# a copy of the License at                                                   #
#                                                                            #
# http://www.apache.org/licenses/LICENSE-2.0                                 #
#                                                                            #
# Unless required by applicable law or agreed to in writing, software        #
# distributed under the License is distributed on an "AS IS" BASIS,          #
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   #
# See the License for the specific language governing permissions and        #
# limitations under the License.                                             #
#--------------------------------------------------------------------------- #

# snap_create host:parent_image snap_id vmid ds_id

SRC=$1
SNAP_ID=$2
VMID=$3

if [ -z "${ONE_LOCATION}" ]; then
    TMCOMMON=/var/lib/one/remotes/tm/tm_common.sh
else
    TMCOMMON=$ONE_LOCATION/var/remotes/tm/tm_common.sh
fi

DRIVER_PATH=$(dirname $0)

source $TMCOMMON
source ${DRIVER_PATH}/../../etc/vmm/kvm/kvmrc

SRC_PATH=$(arg_path $SRC)
SRC_HOST=$(arg_host $SRC)

#-------------------------------------------------------------------------------
# Get Image information
#-------------------------------------------------------------------------------

DISK_ID=$(basename ${SRC} | cut -d. -f2)

XPATH="${DRIVER_PATH}/../../datastore/xpath.rb --stdin"

unset i j XPATH_ELEMENTS

while IFS= read -r -d '' element; do
    XPATH_ELEMENTS[i++]="$element"
done < <(onevm show -x $VMID| $XPATH \
                    /VM/TEMPLATE/DISK\[DISK_ID=$DISK_ID\]/SOURCE \
                    /VM/TEMPLATE/DISK\[DISK_ID=$DISK_ID\]/CLONE \
                    /VM/TEMPLATE/DISK\[DISK_ID=$DISK_ID\]/TARGET \
                    /VM/TEMPLATE/DISK\[DISK_ID=$DISK_ID\]/FORMAT \
                    /VM/DEPLOY_ID \
                    '%m%/VM/TEMPLATE/DISK/TARGET')

DISK_SRC="${XPATH_ELEMENTS[j++]}"
CLONE="${XPATH_ELEMENTS[j++]}"
TARGET="${XPATH_ELEMENTS[j++]}"
FORMAT="${XPATH_ELEMENTS[j++]}"
DEPLOY_ID="${XPATH_ELEMENTS[j++]}"
ALL_DISKS="${XPATH_ELEMENTS[j++]}"

SYSTEM_DS_PATH=$(dirname ${SRC_PATH})
SYSTEM_DS_DISK_PATH="${SYSTEM_DS_PATH}/disk.${DISK_ID}"

if [ "$CLONE" = "YES" ]; then
    DISK_PATH="${SYSTEM_DS_DISK_PATH}"
    DISK_PATH_SHORT="$(basename ${SYSTEM_DS_DISK_PATH})"
else
    DISK_PATH=$DISK_SRC
    DISK_PATH_SHORT=$DISK_PATH
fi

SNAP_DIR="${DISK_PATH}.snap"
SNAP_DIR_SHORT="${DISK_PATH_SHORT}.snap"

if [ "$FORMAT" = "qcow2" ]; then
    NEXT_SNAP_ID=$((SNAP_ID+1))
    SNAP_PATH="${SNAP_DIR}/${NEXT_SNAP_ID}"
    SNAP_PATH_SHORT="${SNAP_DIR_SHORT}/${NEXT_SNAP_ID}"

    # virsh snapshot-create by default creates snapshots for all the disks that
    # are not read only. To be able to make a snapshot in only one of the disks
    # an xml must be created describing all of the disks and setting the value
    # snapshot='no' to the disks that are not going to be snapshotted.

    # <domainsnapshot>
    #   <name>1</name>
    #   <description>snap 1</description>
    #   <disks>
    #     <disk name='vda' snapshot='no'/>
    #     <disk name='vdb'>
    #       <source file='/var/lib/one/datastores/1/09eec196c67b38dea41048a628978600.snap/1'/>
    #     </disk>
    #     <disk name='vdc' snapshot='no'/>
    #   </disks>
    # </domainsnapshot>

    DOC="
    <domainsnapshot>
      <name>${DISK_ID}-${SNAP_ID}</name>
      <description>snap ${DISK_ID}-${SNAP_ID}</description>
      <disks>"

    for disk in $ALL_DISKS; do
        if [ "$disk" = "$TARGET" ]; then
            DOC="$DOC
        <disk name='$disk' snapshot='external'>
          <source file='$SNAP_PATH'/>
        </disk>"
        else
            DOC="$DOC
        <disk name='$disk' snapshot='no'/>"
        fi
    done

    DOC="$DOC
      </disks>
    </domainsnapshot>"

    CREATE_CMD=$(cat <<EOT
        PREVIOUS_SNAP=\$(readlink $SYSTEM_DS_DISK_PATH)

        # Temporary xml file
        FILENAME="/tmp/snapshot-$VMID-$DISK_ID-$SNAP_ID"
        echo "$DOC" > \$FILENAME

        # older qemu-img requires relative backing file paths
        # to be resolvable from the current directory
        cd "${SNAP_DIR}"

        if [ -e "${SNAP_PATH}" ]; then
            echo "Snapshot file ${SNAP_PATH} already exists." >&2
            exit 1
        fi

        $QEMU_IMG create -o backing_fmt=qcow2 -b "\${PREVIOUS_SNAP}" \
            -f qcow2 ${QCOW2_OPTIONS} "${SNAP_PATH}"

        virsh -c $LIBVIRT_URI snapshot-create $DEPLOY_ID --disk-only \
            --atomic --no-metadata --reuse-external --xmlfile \$FILENAME

        rm \${FILENAME}

        ln -sf $SNAP_PATH_SHORT $SYSTEM_DS_DISK_PATH
EOT
)
else
    SNAP_PATH="${SNAP_DIR}/${SNAP_ID}"
    CREATE_CMD="cp \"$DISK_PATH\" \"$SNAP_PATH\""
fi

CMD=$(cat <<EOT
    set -ex -o pipefail
    mkdir -p "$SNAP_DIR"

    if timeout ${VIRSH_TIMEOUT:-60} virsh -c $LIBVIRT_URI domfsfreeze $DEPLOY_ID ; then
        trap "virsh -c $LIBVIRT_URI domfsthaw $DEPLOY_ID" EXIT
    elif virsh -c $LIBVIRT_URI suspend $DEPLOY_ID; then
        trap "virsh -c $LIBVIRT_URI resume $DEPLOY_ID" EXIT
    else
        echo "Could not domfsfreeze or suspend domain" >&2
        exit 1
    fi

    $CREATE_CMD
EOT
)

ssh_exec_and_log "${SRC_HOST}" "${CMD}" \
                 "Error creating snapshot ${SNAP_PATH}"
